John adam smith



(Nd Modell. L

A.; SMIT- HJ Y :1 3ALANGBD PISTON VAL'VL'.v No. 530;,515Qf i Patented 360. `1151894.Y

` `V ure of the iuid prevents the packing-rings tion, and novel featuresY thereof `will be paro the bore of the casing.

Nrrnnj STATES ATENT FFA-ICE JOHN ADAM starrt-I, on JonNsTowN, PENNSYLVANIA, Assieron on Two..`

piTHIRns To JAMES `IIART AND ABRAHAM "WILKINSON, `or sAMr `PLAo` n.

sPEoInIcATIoN forming part of Letters .Patent No. 530,559, daten December 1 1, 1894. l l Application iledAugustSLllQfi. Serial liloJZLSeZ..` (Nomodel.)" l

lo alt whom it,nto/7jconcern:` Be it known that L'JOHN ADAM SMITH,a citizen of the United States, residing at Johnstown, in the countyof Cambria and State of 5 Pennsylvania, have invented a new and use-` ful Balanced Piston Valve, of whichthe fol-A lowing is a specification. V

My invention relates to steam hydraulic, I and similar valves, of the class known as. balanced valves, and the objects in view are to `provide a piston-valve in `which thepressfrom expanding into the ports of the moving part or piston, and at the same time secure a balanced pressureupon'the piston.

Further object'sand advantages of the invention will appear in the following descripticularly pointed out in the appended claims. In the drawings: Figure 1 is a Vertical central section ofa valve embodyingmy invention, the same being` constructed for use `in connection with a double-acting cylinder. Fig. 2 vis a similar section, at right-angles to the plane of Fig. 1, showing the piston 'in its depressed position. 1Fig. 3 is a view of the `bushing cylinder, detached. `Fignt is a view of the piston. l

Similar numerals of reference indicate corresponding parts in' all the figures "of the drawings.

1 designates the valve-casing; preferably cylindrical in construction, which is provided at one end with a cap '2 and at the opposite end with a cap 3 perforated for the stem 4, a stuffing-box 5 being arranged in the cap 3. Communicating withopposite ends of the casing is an exterior duct 6, with which connects the` exhaust-port 7, 'and tapping the casing at itscenter is the inlet port S and. u'pon opposite sides thereof the cylinder-ports 9. The inner surface of the casing, in communication with the inlet-port is channeled as shown' at lO, in communication with the cylinderports is channeled as shownat l11, and in communication withthe terminals ofthe duct 6' is channeled as shown at l2, whereby iiuid, ela-tering or leaving the casing through either all the said openings passes entirely around Arranged in the casing, and entendiug from oneof the end caps to the other, is the cylindrical bushing 1,3, provided opposite each of `the openingsin the casing` with an annular 4 series-of perforations or ports, those opposite 5 5 the inlet port being designated at li, those loppositethe cylinder ports at 15, and those opposite the ends of the exterior duct at 16.

Communicating severally with` these annular series of perforations are the` `channels `17, 6c formed by cutting away the inner surface ofA the'bushing upon opposite sides of theperi forations. j i

The bushing is preferably sectional in construction, the joints between the sections be- 65 ing arranged between the planes lof the various ports, and the terminals'of the sections lbeing fitted withinterposed packing-rings 18grooved asshown at 19 and `fitted upon v the reduced extremities of the sections.` l

Arranged to reciprocate Wit-hin the b ushi ng,

' and connectedfor operation with the stem i,

is the cylindrical piston 20, having closed extremities. i Theendsof the piston are closed by the heads 2l, arranged in` contact with 7 5 annular shoulders 22 formed in the inner suri face of the same, and being held in place by a shoulder` 23 on the stem bearing against lone head and a removable nut 2i threaded u-ponthe extremity' ofthe stem and bearing against 8o the other head; The shoulders 22, orthe seats against which the heads abut, are set back from the ends ,of theshell ofthe piston, and the projecting hollow portions 25are provided with annular seriesof perforations 26 to coin-` 85 municate, successively, with the counterbored i portionsof the bushing, and hence with the terminal ports of the exterior' duct, The shell isfurther provided, at intervals, with annular seriesof ports 27 and28, which are adaptedgo ing through the openings in the bushing enters the bore of the shell and thence passes through the upper cylinder port. It is obviroo' ous that Y'thepressure. -within thes'hell is balanee'd.l n The exhaust fluid, escaping from the cylinder, passes through the other cylinderport, and through the perforations in the extension at the lower end of the shell, thence into the connecting duct, and out through the exhaust-port. This exhaust-fluid, owing to the said duct bears with equal force upon opposite ends ot' the piston, thereby balancing that element. lVhen the position ot' the piston is reversed, as shown in Fig. 2, the conditions are reversed accordingly, and the steam after entering the shell passes through the other cylinder-port, whilefthe 'exhaust-fluid escapes through the upper cylinder-port, and through the perforations in the extension of the upper end oi' the shell, to the exterior duct, and thence to the exhaust-port.

From the above description it will be seen that the pressure of the fluid is from the interior o the shell outward, and hence as the ports of the shell pass the packing-rings the latter are expanded and thus prevented from?l entering or crowding into the latter. Thus, the packing rings are relieved from excessive wear and leakage is prevented.

The pressure of the terminal caps of the casing upon the ends of the bushing holds the latter in place, and when-necessary to replace the packing-rings one of the caps may be removed and the sections of the bushing with` drawn. i

Having described my invention, I claim f vided withports-to register with said inlet and cylinder ports, substantially as specified.

2. The combination of a casing having an exterior duct connecting itsends, and an inlet and a cylinder port, a sectional bushing arranged in the casing, packing-rings interposed between the ends of the sections, and a hollow piston provided with ports to register with the inlet andV cylinder ports, substantially as specified.

3. The combinationyof acasinghavingan .tional bushing provided with ports and counter-bores in communication with the openings in the casing, packing-rings arranged be- 'tween sections of the bushing, and a piston,:

cylindrical in construction, provided with annular series of ports adapted to register withI municating with counterbores, a sectional bushing provided with ports and counterbores, packing-rings interposed between 'the ends of the sections of the bushing, and a hollow piston having closed extremities and in termediate ports adapted to register with the inlet and cylinder ports, and also provided with hollow extensions having openings to register with-the counterbores communicating with the ends of the -said duct, substantially as specified..

5. The combination of a easing provided with'inlet and cylinder ports, communicating with counterbores, and an exterior duct connecting the ends of the casing and also cornmunicating with counterbores, a sectionalA bushing provided with annular series of ports, packing-rings arranged between the extremities ofthe sections of the bushing, and a piston having a cylindrical shell provided with 

